Erm. Although it's styled as a "tribute" to Bill Watterson, I would caution against taking his appreciation of it for granted. Watterson is known to be very protective of his intellectual property per the article linked here.

I am probably the only cartoonist who resented the popularity of his own strip. Most cartoonists are more than eager for the exposure, wealth, and prestige that licensing offers. When cartoonists fight their syndicates, it's usually to make more money, not less. And making the whole issue even more absurd, when I didn't license, bootleg 'Calvin and Hobbes' merchandise sprung up to feed the demand. Mall stores openly sold T-shirts with drawings illegally lifted from my books, and obscene or drug-related shirts were rife on college campuses. Only thieves and vandals have made money on 'Calvin and Hobbes' merchandise.

I dunno, BrewBunny, this seems more an homage in the style of, rather than the wholesale ripping off Watterson so detested. While Joel has lifted visual elements, down to the layout and fonts for the titles he isn't actually using Calvin or Hobbes.

Most importantly, not only is he not using the characters, he also didn't just lift Watterson's images and use them for his own gain, like those t-shirt makers and christian bumper sticker makers I've seen.

B!X, He clearly didn't like other people making money off of his characters. And the big "GET A SIGNED PRINT OF THIS COMIC" for the price of $10 right next to this comic kind of takes this out of the "homage" category and puts it a little closer to the profiting off of someone else's intellectual property category. I'll leave it for the intellectual property lawyers to sort out whether or not Joel has lifted enough visual elements from the original works to constitute actionable infringement. I just wanted to make the point that Watterson is uniquely protective of his characters and should not be assumed to be appreciative of people "paying tribute" to his own work for their own profit.

Calvin's not in the strip. Hobbes isn't either. There is a use of snow to depict morbid events, which is not something you can copyright. It is a homage in the proper use of the word, and not an unauthorized digital reproduction of any of Bill Patterson's intellectual property.

Going purely off the paragraph BrewBunny offered above, because I haven't got time to read the linked article, I'd have to agree that his issue seems to be more about licensing and merchandising than the idea of another artist paying respect to his work. Really don't think he would have an issue with this comic strip at all.

I think it's extremely clever homage. A very clean, cold, and painless death.

Alan's letter: Dear Joel the Bastard Watson, just when I had gotten over my character's untimely death, you dredge it all up again for me. Please find enclosed my therapy bill, you heartless cartoonist...

It totally captures the feel of C&H, and the pain & surprise of Wash's untimely death (Joss, you meanie!!!) and makes you actually giggle, even though his death was terrible and tragic and totally uncalled for (Joss, you big meanie!!!).